The structure and binding mode of interleukin-18
Kato, Z., Jee, J., Shikano, H., Mishima, M., Ohki, I., Ohnishi, H., Li, A., Hashimoto, K., Matsukuma, E., Omoya, K., Yamamoto, Y., Yoneda, T., Hara, T., Kondo, N., Shirakawa, M.(2003) Nat Struct Biol 10: 966-971
- PubMed: 14528293 
- DOI: https://doi.org/10.1038/nsb993
- Primary Citation of Related Structures:  
1J0S - PubMed Abstract: 
Interleukin-18 (IL-18), a cytokine formerly known as interferon-gamma- (IFN-gamma-) inducing factor, has pleiotropic immunoregulatory functions, including augmentation of IFN-gamma production, Fas-mediated cytotoxicity and developmental regulation of T-lymphocyte helper type I. We determined the solution structure of IL-18 as a first step toward understanding its receptor activation mechanism. It folds into a beta-trefoil structure that resembles that of IL-1. Extensive mutagenesis revealed the presence of three sites that are important for receptor activation: two serve as binding sites for IL-18 receptor alpha (IL-18Ralpha), located at positions similar to those of IL-1 for IL-1 receptor type I (IL-1RI), whereas the third site may be involved in IL-18 receptor beta (IL-18Rbeta) binding. The structure and mutagenesis data provide a basis for understanding the IL-18-induced heterodimerization of receptor subunits, which is necessary for receptor activation.
Organizational Affiliation: 
Department of Pediatrics, Gifu University School of Medicine, Tsukasa 40, Gifu 500-8705, Japan. zen-k@cc.gifu-u.ac.jp